title: Estimation of the effect of dalfampridine-ER on health utility by mapping the MSWS-12 to the EQ-5D in multiple sclerosis patients.
abstract: BACKGROUND
  Trials have not assessed the effect of dalfampridine-extended release (dalfampridine-ER) on health utility. We sought to evaluate the effect of dalfampridine-ER tablets (prolonged-release fampridine in Europe) on health utility in patients with multiple sclerosis (MS) by mapping subjects' individual item scores from the 12-Item Multiple Sclerosis Walking Scale (MSWS-12) onto the Euroqol 5-Dimension (EQ-5D) health utility index.
  
  
  METHODS
  Data from study MS-F203, a randomized trial of dalfampridine-ER tablets, 10 mg twice daily, in patients with MS, were used to calculate the health utility scores with two MSWS-12 to EQ-5D mapping equations (one derived in a North American [NA] registry, the other a United Kingdom [UK] registry). MS-F203 participants were categorized as dalfampridine-ER 20%-responders (achieving ≥20% improvement on the Timed 25-Foot Walk), dalfampridine-ER 20%-nonresponders (<20% improvement), or placebo patients. Mean change in health utility scores from baseline to each double-blind treatment evaluation (visits 3-6 occurring at post-randomization weeks 2, 6, 10, and 14) and each off-drug follow-up evaluation (visits 7-8 occurring at weeks 16 and 18) were calculated and reported as effect sizes (ESs).
  
  
  RESULTS
  Using the NA-derived equation, dalfampridine-ER 20%-responders demonstrated improvement in health utility vs. placebo; starting at week 6 (mean difference in ES = 0.44, p = 0.002) and maintained at weeks 10 (ES = 0.41, p = 0.01) and 14 (ES = 0.71, p < 0.001). These improvements were no longer evident after dalfampridine-ER was discontinued (p > 0.05 at weeks 16 and 18). Dalfampridine-ER 20%-nonresponders did not show improvement vs. placebo at any visit (p > 0.05 for all). When using the UK-derived equation, improvement was seen in dalfampridine-ER 20%-responders vs. placebo at weeks 2, 6, 10, and 14 (ESs = 0.49, 0.55, 0.59, and 0.99; p < 0.03 for all), but not when dalfampridine-ER was discontinued (weeks 16 and 18; p > 0.05 for both). Dalfampridine-ER 20%-nonresponders showed no improvement at any visit (p > 0.05 for all).
  
  
  CONCLUSIONS
  Regardless of the equation used, dalfampridine-ER response was associated with an improvement in health utility.
authors.forename: Brendan L
authors.initials: BL
authors.lastname: Limone
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Sidovar
authors.forename: Craig I
authors.initials: CI
authors.lastname: Coleman
mesh_terms: D015761:4-Aminopyridine / Q000008:administration & dosage / Q000627:therapeutic use*; D000284:Administration, Oral; D000293:Adolescent; D000328:Adult; D000368:Aged; D002170:Canada; D003692:Delayed-Action Preparations; D004311:Double-Blind Method; D004334:Drug Administration Schedule; D005060:Europe; D005260:Female; D006304:Health Status; D006801:Humans; D008297:Male; D008875:Middle Aged; D051346:Mobility Limitation; D009103:Multiple Sclerosis / Q000150:complications / Q000175:diagnosis / Q000188:drug therapy*; D009460:Neurologic Examination; D017063:Outcome Assessment, Health Care; D010919:Placebos; D026902:Potassium Channel Blockers / Q000008:administration & dosage / Q000627:therapeutic use*; D011788:Quality of Life / Q000523:psychology*; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires; D013607:Tablets; D016896:Treatment Outcome; D014481:United States; D016138:Walking / Q000502:physiology*; D055815:Young Adult
chemical_list: D003692:Delayed-Action Preparations; D010919:Placebos; D026902:Potassium Channel Blockers; D013607:Tablets; D015761:4-Aminopyridine